An accurate center frequency tuning scheme for 450-KHz CMOS G/sub m/-C bandpass filters

This paper describes a center frequency tuning technique for a second intermediate-frequency (IF) bandpass filter. The utilization of the step signal response ensures the direct measurement of the center frequency. This tuning technique guarantees the accuracy of the design. A 450-kHz G/sub m/-C bandpass filter tuned using this technique has been developed to integrate the IF module for personal digital cellular (PDC) handsets for use in 0.35-/spl mu/m CMOS. The filter with the tuning scheme achieves a center frequency accuracy of /spl plusmn/0.5%.